ABSTRACTS POSTERS WETENSCHAPSDAG SFG 2012 INTRODUCTION: In most patients euthyroidism, thyrotoxicosis or hypothyroidism is confirmed with the combination of free T4 (FT4) and thyroxin stimulating hormone (TSH) measurements. Discrepancies between thyroid function tests and the patient’s clinical status should question immunoassay validity. Merely relying on the thyroid function tests may lead to inappropriate treatment. In this study we evaluate several interfering antibodies on four different thyroid hormone immunoassays and the gold standard equilibrium dialysis in order to investigate possible methods to overcome these. MATERIAL AND METHODS: We performed FT4 measurements on four different analyzers (Cobas Modular; Roche, Immulite 2500; Siemens, DXi; Beckman Coulter, Vitros Eci; Ortho Clinical Diagnostics) and compared these to the gold standard equilibrium dialysis. Two patients with aberrant free T4 (FT4) results, two patients with human anti-mouse antibodies (HAMA) and rheumatoid factor (RF), respectively and two external quality samples were included in this study. All samples were measured before and after treatment with heterophilic blocking tubes (Scantibodies Laboratory) or protein A/G agarose beads (Thermo Scientific). RESULTS: Surprisingly the HAMA (2464 ng/ml) and RF (440 IU/ml) positive samples showed no interference on four different FT4 immunoassays and the dialysis method. Aberrant FT4 patient results were only encountered in the Immulite immunoassay whereby the results were falsely elevated. This interference was eliminated after treatment with protein A/G agarose beads but not after heterophilic blocking tube treatment. Furthermore, no thyroid hormone auto-antibodies (THAA) were detected using gel electrophoresis. Remarkably both samples were positive for anti-thyreoglobuline (anti-TG). Heterophilic blocking tube and protein A/G treatment had no significant effect on FT4 results in the external quality samples. CONCLUSION: Anti-TG is a possible cause of interference in the Immulite immunoassay giving falsely elevated results. Treatment with protein A/G, but not heterophilic blocking tube treatment, removed the antibody interference. HAMA, RF and anti-TG exhibit no interference on the Modular, DXi, Vitros analysers or the dialysis method. Furthermore, treatment with protein A/G or heterophilic blocking tube gave reproducible FT4 results. Leukocyte differentiation by flow cytometry: comparison of two protocols, Leukoflow and CytodiffTM, with microscopy and hematology analyzer. Gert-Jan van de Geijn, Maarten van Dijk, Rita Meijer, Yolanda Blaauw, Rene Bakker, Hans Janssen, Marlène Beunis, Tjin Njo Department of Clinical Chemistry (KCHL), Sint Franciscus Gasthuis, Rotterdam. INTRODUCTION: Leukocyte differential counting is a frequently performed diagnostic test. When the automated leukocyte differential generated by a hematology analyser does not meet specific criteria, a microscopic differential is performed. Disadvantages of microscopy are the limited number of counted cells and significant statistical and inter-observer variation. Several laboratories published flow cytometric protocols to perform single-tube leukocyte differentials. Advantages over microscopy are the increased number of counted cells (several ten-thousands) and objective immunological definitions of an increased number of leukocyte populations. Comparison of different flow cytometric protocols on a single data set has not been reported yet. GOAL: The aim of this study was to compare 2 different flow cytometric leukocyte differentiations: Leukoflow (developed by us) and CytodiffTM (Beckman Coulter) with the results from the hematology analyzer and microscopy. 115 WETENSCHAPPELIJK jaarverslag 2012 Pagina 114
Pagina 116Voor PDF's, online uitgaves en whitepapers zie het Online Touch CMS systeem. Met de mogelijkheid voor een e-commerce shop in uw maandbladen.
SFG Jaarverslag 2012 Lees publicatie 130Home